Re: [PATCH v4 1/5] selftests/x86: Use getauxval() to simplify the code in sgx

Jarkko Sakkinen
2021-02-02T22:04:52Z

On Mon, Feb 01, 2021 at 09:26:49PM +0800, Tianjia Zhang wrote:
> Simplify the sgx code implemntation by using library function
> getauxval() instead of a custom function to get the base address
> of vDSO.
>
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

This needs also ack from Shuah.

/Jarkko

> ---
> tools/testing/selftests/sgx/main.c | 24 ++++--------------------
> 1 file changed, 4 insertions(+), 20 deletions(-)
>
> diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
> index 724cec700926..5167505fbb46 100644
> --- a/tools/testing/selftests/sgx/main.c
> +++ b/tools/testing/selftests/sgx/main.c
> @@ -15,6 +15,7 @@
> #include <sys/stat.h>
> #include <sys/time.h>
> #include <sys/types.h>
> +#include <sys/auxv.h>
> #include "defines.h"
> #include "main.h"
> #include "../kselftest.h"
> @@ -28,24 +29,6 @@ struct vdso_symtab {
> Elf64_Word *elf_hashtab;
> };
>
> -static void *vdso_get_base_addr(char *envp[])
> -{
> - Elf64_auxv_t *auxv;
> - int i;
> -
> - for (i = 0; envp[i]; i++)
> - ;
> -
> - auxv = (Elf64_auxv_t *)&envp[i + 1];
> -
> - for (i = 0; auxv[i].a_type != AT_NULL; i++) {
> - if (auxv[i].a_type == AT_SYSINFO_EHDR)
> - return (void *)auxv[i].a_un.a_val;
> - }
> -
> - return NULL;
> -}
> -
> static Elf64_Dyn *vdso_get_dyntab(void *addr)
> {
> Elf64_Ehdr *ehdr = addr;
> @@ -162,7 +145,7 @@ static int user_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r
> return 0;
> }
>
> -int main(int argc, char *argv[], char *envp[])
> +int main(int argc, char *argv[])
> {
> struct sgx_enclave_run run;
> struct vdso_symtab symtab;
> @@ -203,7 +186,8 @@ int main(int argc, char *argv[], char *envp[])
> memset(&run, 0, sizeof(run));
> run.tcs = encl.encl_base;
>
> - addr = vdso_get_base_addr(envp);
> + /* Get vDSO base address */
> + addr = (void *)getauxval(AT_SYSINFO_EHDR);
> if (!addr)
> goto err;
>
> --
> 2.19.1.3.ge56e4f7
>
>